To analyze the acceleration responses of projectiles under various projectile structures or closed-cell foam aluminum material parameters,a nonlinear dynamics finite element model of a projectile impacting closed-cell foam aluminum is established.The waveform of a projectile impacting closed-cell foam aluminum is simulated by LS-DYNA software.The influences of different parameters on impulse response are researched by a numerical method.The trend,peak value and pulse width of the acceleration curves under different conditions are studied respectively.The results show that a smooth acceleration waveform can be obtained by using conical projectiles.The peak acceleration increases and the pulse width reduces under such conditions as lower porosity,thinner target and smaller mass of the projectile.High initial speed of the projectile can increase the peak value and the pulse width of the acceleration.